JPH0522129A - Phase synchronizing detection circuit - Google Patents

Abstract

PURPOSE:To realize the phase synchronizing detection circuit, which unnecessitates the control of a reference voltage and automatically follows up a power supply voltage fluctuation or a temperature fluctuation, by constituting a reference voltage generating circuit having the same package circuit configuration as a phase comparator and a phase detector. CONSTITUTION:This phase synchronizing detection circuit to monitor the phase synchronizing state of a phase synchronizing oscillator is equipped with first means 1 and 2 to extract the output of a logic element, which compares the phases of an input signal and an inside reference signal, as an integrating value, second means 3 and 4 to input the above-mentioned reference signal and to extract the output of the same logic element as the above-mentioned first means 1 and 2 as the integrating value while using this logic element, and means 5 to input the output signals of the first and second means and to execute the comparison and judgement of those signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase lock detecting circuit, and more particularly to a phase lock detecting circuit for stabilizing a phase lock pull-in range in a phase locked oscillator (PLO) using a phase locked loop (PLL).

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a phase synchronization detection circuit 9 in a digital signal transmission type equal phase synchronization oscillator (PLO) has a phase comparator 1, a phase detector 2, a reference voltage generation circuit 8 and a comparison judgment. It is composed of a container 5 and forms a PLL with an external VCO 6. This PL
As a method of confirming the synchronization state of O, for example, the PLO phase comparator 1 is EX-
When configured by OR, the input signal 101 and the internal reference signal 102 are phase-compared, integrated by the phase detector 2, and then compared with a fixed voltage generated by the reference voltage generation circuit 8 by the comparison / determination unit 5 and synchronized. The condition is detected.

[0003]

In the conventional phase detection circuit described above, a highly stable voltage source is made up of a Zener diode or the like as a reference, and the reference voltage is always used in order to absorb a slight variation of the element. Must be adjusted. Further, there is a drawback in that the determination standard is changed because the variation of the outputs of the phase comparator 1 and the phase detector 2 and the variation of the reference voltage generating circuit 3 serving as a reference are not correlated due to the power supply voltage variation and the temperature variation.

[0004]

The phase synchronization detection circuit of the present invention is a phase synchronization detection circuit for monitoring the phase synchronization state of a phase synchronization oscillator, and outputs the output of a logic element for phase comparison between an input signal and an internal reference signal. First means for taking out as an integrated value, second means for receiving the reference signal and using the same logic element as the first means, and taking out the output of this logical element as an integrated value, the first and the second means. 2 means for inputting the output signal of the second means for comparison and determination.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is an operation explanatory diagram of this embodiment. In FIG. 1, the phase comparator 1 is EX
An input signal 101
And the phase difference between the internal reference signal 102 and the phase difference signal 103 are output according to the phase difference between the two. The phase detector 2 has a integrating function such as a CR integrating circuit and integrates the phase difference signal 103 and outputs a phase difference detection voltage 104. The reference voltage generation circuit 3 is composed of elements such as EX-OR in the same IC package as the phase comparator 1,
Similarly, it is combined with the reference voltage detector 4 having a C-R integration function and the like, and always integrates the level of the internal reference signal 102 and outputs it as the reference voltage 105. By using the EX-OR in the same package for the reference voltage generation circuit 3 and the phase comparator 1, the reference voltage generation is performed individually because it changes in association with the power supply voltage fluctuation and the temperature fluctuation of the entire phase comparison circuit. Correction can be performed more easily and more accurately than if a circuit is provided. The comparison / determination device 5 compares the phase difference detection voltage 104 from the phase detector 2 with the reference voltage 105 from the reference voltage detector 4 and outputs a comparison determination signal 106. At this time, the input / output signal 1
Even if noise or the like is added to 01 and the internal signal 102, the erroneous determination of the comparison and determination unit 5 can be prevented.

FIG. 2A shows the phase-locking characteristic of a general PLO, and FIG. 2B shows the characteristic of the comparison judgment signal 106 of the detection circuit in the phase-locked state corresponding to this phase-locking range. There is. Now, as an example, the operation when the power supply voltage becomes high will be described. In FIG. 2B, it is assumed that the output of the synchronization detector is VD1 when the power supply is normal, and the reference voltage for synchronization determination is given as Vr1. When the power supply voltage increases by ΔV, the output of the synchronization detector becomes VD2, which increases by ΔVD. According to the present invention, since the reference voltage uses the IC of the same package as the wave detector, the reference voltage also becomes Vr2 and increases by ΔVD, and the synchronization determination with less error can be performed.

[0007]

As described above, the phase-locking detection circuit of the present invention constitutes a reference voltage generating circuit having the same circuit configuration as the phase comparator and the phase detector, so that the reference voltage is not adjusted. Further, there is an effect that it is possible to realize a phase synchronous detection circuit that automatically follows a power supply voltage fluctuation and a temperature fluctuation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating characteristics of the present embodiment.

FIG. 3 is a configuration diagram of a conventional phase synchronization detection circuit.

[Explanation of symbols]

1 Phase comparator 2 Phase detector 3,8 Reference voltage generation circuit 4 Reference voltage detector 5 Comparative judgment device 6 VCO 7,9 Phase synchronization detection circuit

Claims (2)

[Claims] 1. A phase synchronization detection circuit for monitoring a phase synchronization state of a phase synchronization oscillator, comprising: first means for extracting an output of a logic element for phase comparison between an input signal and an internal reference signal as an integrated value; A second means for inputting a signal and using the same logic element as the first means to take out the output of this logic element as an integrated value and the output signals of the first and second means are inputted and compared and judged. And a phase synchronization detection circuit. 2. The phase synchronization according to claim 1, wherein the circuits of the first means and the second means are formed as ICs in the same package and are configured to operate with the same power supply. Detection circuit.